Tang Yun and Zheng Yun explain the pronunciation using the character for fermented beans, pronounced yi (falling tone). Shuowen Jiezi explains it as meaning light in weight. In ancient times, the character for change was borrowed and read with a falling tone, carrying the same meaning. It is different from the character for injured. Additionally, another interpretation in Shuowen Jiezi refers to trade or exchange, which is easily confused with the character for change that denotes mutual markets.